Banish black tank smells forever with these simple steps! Don’t be afraid to use your RV bathroom. Not having to use public restrooms or bathhouses when we travel is one of the reasons we love RV travel.
We’ve been living and traveling full-time in our RV for four years, using our bathroom just as we did in our sticks & bricks home. Even in the sweltering summer heat (we spent a couple in Florida), we were able to keep our bathroom and RV odor free by using the method we’ll outline in this post.
Continue on to read our step by step process or watch the video below.
Step 1. Keep the tanks closed until ready to flush.
If you are at a location with a sewer connection, you may be tempted to keep your camper’s black tank valve open and let the sewage flow freely. Don’t. This will result in the dreaded poop pyramid. Ever use a open pit toilet? You know the ones with no water at the bottom. Everything just starts building up. You need a lot of water to keep things flowing smoothly. In fact, I usually refill the toilet and give it an extra flush after most uses just to keep plenty of water in the tank. This will also help dissolve the toilet paper fully. Bottomline: Water is your friend and keep the tank valve closed until you are ready to dump.
Step 2. Flush the tank regularly.
It is important to flush your RV black tank regularly. This is easiest when you are at a campground with sewer hook ups. We empty our black tank about every 5 – 7 days. If it is not 3/4 full, we add water to assist in completely draining the tank. We also recommend emptying it before travel to reduce the extra weight (water weighs ~8 lbs per gallon).
- Open the valve and the drain the black tank completely.
- Back flush the camper black tank. Our main black tank has the built in backflush inlet that most newer RVs come with. The black tank for the 2nd bathroom does not, so we purchased a Camco Dual Flush Pro Holding Tank Rinser (click image below for more detail). We back fill our tank for 4 minutes. Drain and repeat 1-2 times until the water is clear. I used to run inside and watch the tank monitor, but that got old so now I stay outside and time it.
- Once the water is running clear, close the black tank valve, and backfill the black tank with about 2 gallons of water. Since we have the built in system, we just time it for 90 seconds. If you don’t have that, you can do it from inside by flushing the toilet and letting the water flow down into the holding tank for that long.
- We follow a black tank drain and flush cycle with a gray tank flush. We also have two gray tanks — one for the main bathroom (sink/shower) and one for the kitchen and second shower. If are at a site with sewer hook ups, we leave the main one closed until we’re ready to dump the black. We leave the 2nd gray tank open to drain as water is used. If you only have one gray tank and want to leave it open most of the time, we recommend closing it a day or two prior to your black tank flush so you can essentially wash out the sewer hose with the soapy gray water.
- Finally, when we get back inside the RV, we add two capfuls of Calgon water softener and about 1/2 cup to 1 cup of of liquid dish detergent (some people say Dawn, but we use a generic).
Step 3. Remember, Water is Your Friend
As previously mentioned, using plenty of water is the best thing to keep the RV black tanks flowing smoothly. Don’t be afraid to use it. We both often flush an extra time or two just to add water to the holding tank.
Water availability was a problem we encountered with our first boondocking experience. Also, although we were able to use the portable sewage system, we didn’t have enough water available to back flush the tank as we described above. Our solution was to drive to a dump station every other week. In the future we will bookend boondocking or partial hook up stays with full hook up campground stays.
Learn More About Your RV Water Systems
Check out our book, A Complete Novice’s Guide to RV Water System’s Maintenance you want to learn more about your RV water systems, from preventive maintenance like flushing the water heater to sanitizing the fresh water tanks. It’s short, full of photos, and written in laymen’s terms. Even better, its free on Amazon Kindle Unlimited!
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Very informative and interesting. Thanks!
You’re welcome! We’re glad you found it helpful and are especially glad you stopped by our site.
I wonder how long opening and closing opening and closing the black water tank valve will last?
4 years so far, but we’ll post an update when it gives out.
Thank you so much I am trying to prove that I know what I know is right to a couple who thinks they know but seems I knew better than them who always leave their valves open the whole time
Thanks again
Glad you agree with us! 🙂 This is just what we have found works best for us.
We are very new to camping and was told to never leave the valves open, not just for smell, but god knows what could crawl up the piping…no Thanks!!!
The main reason you don’t want to leave your black tank valve open is because you need a lot of water so things will flow out when you want them too (not pile up). 🙂
Thanks for the tips. But any feedback on storing the camper for a couple very hot months. It smells bery bad i assume any water left just dries up. I usually backflush a few times. But my issuse is when i return .
Hmm, that’s a good question. Since we are full-time travelers we really don’t ever leave the RV for that long. I would recommend going on a FB Group called RV Family Travel Atlas. It is geared more towards part-time RVers so they would understand the concerns of storage. Everyone in that group is always super helpful too. Sorry I couldn’t be more help on that one!
I use pine sol in our black tank when I store ours!
I’ve read these types of comments many times. My “solution” is to camp for several days before I even connect the sewer line. I usually don’t for an overnight in a pull through site. And I never leave the tanks open, except when emptying them. The value is that we get set up in our campsite faster.
Our sewer connection from the RV is under the slide so it is simpler to go ahead and connect that first thing. However, we don’t leave the black tank open either.
“Finally, when we get back inside the RV, we add two capfuls of Calgon water softener and about 1/2 cup to 1 cup of of liquid dish detergent (some people say Dawn, but we use a generic)“
Is this added to the gray tank or black tank or both”
Just the black. The soap will get in the gray from showering and dish washing.
Do you use this combination instead of the solutions sold for black tanks? None of those have been very effective for us.
Yes, we use this instead of any chemicals or deodorant packs in the black tank.
Do you still add black tank chemicals to your tank or just use Calgon?
No chemicals, just the Calgon & dish soap.
I’m sorry I’m so confused lol. So once you add the 2 gallons of water, you leave that in the tank correct? You don’t empty that out right? We are very new to this and neither myself nor husband has a clue, so thank you so much for the post. We would be lost without information like this lol.
No problem. I emailed you a more in depth answer, but yes, you are right. At the end of the process, you add back in a gallon or two of water and leave it there with the Calgon and dish soap. You always want to have water in your black tank before you use it.
these are great tips, we are very new, first summer as a matter of fact. We have been told to add an enzyme product to break down everything in black tank, but you don’t mention it. just wanting to know. Thank you!
We used an enzyme product our first year on the road. It didn’t seem to work any better than the other additives. I think that is because you don’t keep things in your black tank long enough for them to break down really. For the last 4 years we’ve only used the Calgon & dish soap.
We got samples of an excellent natural enzyme product when we bought our first camper. The company has since gone out of business and we haven’t found anything comparable. Looking forward to trying your tip this summer.
We used some kind of enzyme early on too. When I couldn’t find it again, I started using this method.